JSFiddle - React, Tailwind, and code Playground

JavaScript

Object.defineProperty(Array.prototype, 'insert', {
  enumerable: false,
  value: function(index, element){
    this.splice(index, 0, element);
  }
});
var a = [1,2,3];
a.insert(0, 4);
console.log(a);
for (i in a) console.log(i, a[i]);